Substrate Including Nano/Micro Structure, Method for Manufacturing the Same, Method for Refining Nano/Micro Structure, Method for Manufacturing Nano/Micro Structure Network, and Manufacturing Apparatus Therefor

ABSTRACT

Provided is a manufacturing method for a substrate having a microstructure. The manufacturing method for a substrate having a microstmcture comprises the steps of: forming a microstructure on the upper surface of an auxiliary substrate; coating a base solution on the microstructure; forming a base substrate covering the microstructure by heattreating the base solution; and removing the auxiliary substrate from the base substrate.

TECHNICAL FIELD

The present disclosure relates to a substrate including nano/microstructures, a method for manufacturing the same, a method for refining anano/micro structure, a method for manufacturing a nano/micro structurenetwork, and a manufacturing apparatus therefor.

BACKGROUND ART

A micro/nano structure having a size of several nm to several hundred nmis manipulated and controlled in nano scale. Thus, new physical/chemicalproperties different from those of existing materials can be expected.Therefore, the micro/nano structure has been attracting a lot ofattention as a next-generation material which can overcome thelimitations of the existing materials.

Such a micro/nano structure is one type of core new material thatprovides a foundation for use in technologies of various fields such asorganic light emitting elements, liquid crystal displays, touch panels,or solar cells. Generally, a micro/nano structure is manufactured tovarious sizes by a chemical method, and micro/nano structures are coatedon a substrate by bar coating, spray coating, spin coating, dip coating,brush coating, gravure coating, or the like. Various techniques formanufacturing a substrate including micro/nano structures with excellentproperties have been developed.

For example, Korean Patent Laid-open Publication No. 10-2013-0037483(Application No. 10-2011-0101907) discloses a method for manufacturing aconductive film by forming a one-dimensional conductive nanomaterialincluding any one selected from a carbon nanotube, a metal nano wire,and a metal nano rod and forming a two-dimensional nanomaterialincluding any one selected from graphene, boronitride, and tungstenoxide on an upper surface of the one-dimensional conductivenanomaterial.

Meanwhile, if micro/nano structures having different sizes are used in atransparent electrode or the like, conductivity and transmittance aredecreased and haze is increased. Accordingly, various techniques formanufacturing uniform-sized micro nano structures have been developed.

For example, Korean Patent Laid-open Publication No. 10-2013-0072956(Application No. 10-2011-0140589) discloses a method for forming a metalnano wire by allowing a reaction solution to pass through a filterhaving a pore size of 5 μm to 10 μm.

Further, various techniques for reducing a resistance of a micro/nanostructure network have been developed. Particularly, as for a silvernano wire, there has been suggested a method of performing a heattreatment, an acid steam treatment, and a graphene oxide treatment aftercoating. However, such methods have a problem of damaging micro/nanostructures or a substrate on which the micro/nano structure aredisposed.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

An object to be achieved by the present disclosure is to provide asubstrate including nano/micro structures with a minimized surfaceroughness and a method for manufacturing the same.

Another object to be achieved by the present disclosure is to provide asubstrate including nano/micro structures with high reliability and amethod for manufacturing the same.

Yet another object to be achieved by the present disclosure is toprovide a substrate including flexible nano/micro structures and amethod for manufacturing the same.

Still another object to be achieved by the present disclosure is toprovide a substrate including transparent and conductive nano/microstructures and a method for manufacturing the same.

Still another object to be achieved by the present disclosure is toprovide a refining method and a refining apparatus for a nano/microstructure with high reliability.

Still another object to be achieved by the present disclosure is toprovide a refining method and a refining apparatus for nano/microstructures having substantially the same size.

Still another object to be achieved by the present disclosure is toprovide a refining method and a refining apparatus for a nano/microstructure which can be simply manufactured.

Still another object to be achieved by the present disclosure is toprovide a refining method and a refining apparatus for a nano/microstructure which can be improved in production yield.

Still another object to be achieved by the present disclosure is toprovide a refining method and a refining apparatus for a nano/microstructure applicable to a continuous process.

An object to be achieved by the present disclosure is to provide amanufacturing method and a manufacturing apparatus for a nano/microstructure network which can have a substantially uniform sheetresistance.

Another object to be achieved by the present disclosure is to provide amanufacturing method and a manufacturing apparatus for a nano/microstructure network with a minimized resistance.

Yet another object to be achieved by the present disclosure is toprovide a manufacturing method and a manufacturing apparatus for anano/micro structure with minimized damage to a substrate.

The objects to be achieved by the present disclosure are not limited tothe above-described objects.

Technical Solution

In order to achieve the above-described aspects, the present disclosureprovides a method for manufacturing a substrate including nano/microstructures.

According to an exemplary embodiment, the method for manufacturing asubstrate including nano/micro structures includes: forming nano/microstructures on an upper surface of an auxiliary substrate; coating a basesolution on the nano/micro structures; forming a base substrateconfigured to cover the nano/micro structures by performing a heattreatment to the base solution; and removing the auxiliary substratefrom the base substrate.

According to an exemplary embodiment, during the heat treatment to thebase solution, at least parts of the nano/micro structures may be fusedand bonded to each other.

According to an exemplary embodiment, there is a gap between thenano/micro structures and the auxiliary substrate, and the base solutionfills the gap.

According to an exemplary embodiment, the nano/micro structures aredisposed within the base substrate.

According to an exemplary embodiment, the method for manufacturing asubstrate including nano/micro structures may further include:performing a pretreatment process for reducing surface energy of theupper surface of the auxiliary substrate before forming the nano/microstructures on the auxiliary substrate.

According to an exemplary embodiment, the method for manufacturing asubstrate including nano/micro structures may further include: at leastone of performing a heat treatment to the auxiliary substrate on whichthe nano/micro structures are formed before coating the base solutionand performing a heat treatment to the base substrate after separatingthe auxiliary substrate.

According to an exemplary embodiment, the method for manufacturing asubstrate including nano/micro structures may further include: forming areleasing layer on the upper surface of the auxiliary substrate beforeforming the nano/micro structures. The nano/micro structures are formedon the releasing layer, and the separating of the auxiliary substratefrom the base substrate may include removing the releasing layer.

According to an exemplary embodiment, the auxiliary substrate is removedfrom the base substrate to expose a main surface of the base substrateadjacent to the upper surface of the auxiliary substrate.

According to an exemplary embodiment, the main surface of the basesubstrate may include a portion including the nano/micro structures anda portion including the base substrate.

According to an exemplary embodiment, the method for manufacturing asubstrate including nano/micro structures may further include: forming aconductive film on the main surface of the base substrate.

In order to achieve the above-described aspects, the present disclosureprovides a method for manufacturing an electronic element.

According to an exemplary embodiment, the method for manufacturing anelectronic element may further include: manufacturing the substrateincluding nano/micro structures according to the above-describedexemplary embodiments; and forming a semiconductor element on the mainsurface of the base substrate.

In order to achieve the above-described aspects, the present disclosureprovides a substrate including nano/micro structures.

According to an exemplary embodiment, the substrate including nano/microstructures includes a base substrate including a flat main surface andnano/micro structures disposed within the base substrate so as to beadjacent to the main surface. The main surface of the base substrate mayinclude a first portion including the base substrate and a secondportion including the nano/micro structures.

According to an exemplary embodiment, the base substrate includes acounter surface facing the main surface, and the nano/micro structuresare disposed within the base substrate and located relatively closer tothe main surface than to the counter surface.

According to an exemplary embodiment, the nano/micro structures includean exposed portion constituting the main surface and a dent portionlocated under the main surface. The dent portion is covered by the firstportion of the main surface.

In order to achieve the above-described aspects, the present disclosureprovides a method for refining a nano/micro structure.

According to an exemplary embodiment, the method for refining anano/micro structure may include: preparing a mixed solution includingstructures different from each other in mass; spreading the mixedsolution including the structures on a substrate by supplying the mixedsolution onto the substrate; collecting a part of the mixed solutionspread on the substrate; and recovering the structures included in thecollected part of the mixed solution from the collected part of themixed solution.

According to an exemplary embodiment, the structures may be silver nanostructures.

According to an exemplary embodiment, the substrate is inclined to theground.

According to an exemplary embodiment, the collected part of the mixedsolution is located within a predetermined distance range from alocation at which the mixed solution is supplied to the substrate.

According to an exemplary embodiment, the collecting of the part of themixed solution may include: removing the mixed solution spread on thesubstrate except the part of the mixed solution; and collecting theremaining part of the mixed solution.

According to an exemplary embodiment, the spreading of the mixedsolution may include: drying the mixed solution, and the collecting ofthe part of the mixed solution may include: collecting the part of thedried mixed solution.

According to an exemplary embodiment, the collecting of the part of themixed solution may include: supplying a solution that dissolves the partof the dried mixed solution onto the substrate.

According to an exemplary embodiment, the recovering of the structuresmay include: recovering the structures from the solution in which thepart of the mixed solution is dissolved, with a centrifuge.

According to an exemplary embodiment, the method for refining anano/micro structure may further include: forming a peeling layer on thesubstrate before supplying the mixed solution onto the substrate.

According to an exemplary embodiment, the peeling layer is dissolved bythe solution.

According to an exemplary embodiment, the method for refining anano/micro structure may further include: performing a pretreatmentprocess for reducing surface energy of a surface of the substrate beforesupplying the mixed solution onto the substrate.

In order to achieve the above-described aspects, the present disclosureprovides a refining apparatus for a nano/micro structure.

According to an exemplary embodiment, the refining apparatus for anano/micro structure may include: a substrate including an upper surfaceinclined to the ground; and a mixed solution supply unit configured tosupply a mixed solution including structures different from each otherin mass to the upper surface of the substrate. The structures havingrelatively small mass are spread farther from a location where the mixedsolution is supplied to the upper surface of the substrate than thestructures having relatively great mass.

According to an exemplary embodiment, the refining apparatus for anano/micro structure may further include an inclination adjusting unitconfigured to adjust an inclination between the upper surface of thesubstrate and the ground.

According to an exemplary embodiment, the refining apparatus for anano/micro structure may further include a substrate pretreatment supplyunit configured to supply plasma to the upper surface of the substrate.

According to an exemplary embodiment, the mixed solution supply unit maysupply the mixed solution including the structures to a part of theupper surface of the substrate placed at a relatively high location fromthe ground.

According to an exemplary embodiment, the substrate may be providedplural in number and upper surfaces of the plurality of substrates maybe inclined to the ground. Parts of the upper surfaces of the pluralityof substrates placed at a relatively high location from the ground maybe disposed to be adjacent to each other.

According to an exemplary embodiment, the upper surfaces of theplurality of substrates may be increased in size as being closer to theground.

In order to achieve the above-described aspects, the present disclosureprovides a method for manufacturing a nano/micro structure network.

According to an exemplary embodiment, the method for manufacturing anano/micro structure network may include: forming a base layer includingconductive structures on a substrate; forming a first network in which afirst point of the base layer and a second point separated from thefirst point are electrically connected by the structures by applying acurrent between the first point and the second point; and forming asecond network in which a third point of the base layer and a fourthpoint separated from the third point are electrically connected by thestructures by applying a current between the third point and the fourthpoint.

According to an exemplary embodiment, the structures may include silvernano structures.

According to an exemplary embodiment, at least parts of the structuresare bonded to each other by the current applied between the first pointand the second point and the current applied between the third point andthe fourth point.

According to an exemplary embodiment, the first to fourth points arelocated at edges of the base layer.

According to an exemplary embodiment, the current applied between thefirst point and the second point and the current applied between thethird point and the fourth point respectively have current pathsdifferent from each other.

According to an exemplary embodiment, the current applied between thefirst point and the second point corresponds to the first network andthe current applied between the third point and the fourth pointcorresponds to the second network.

In order to achieve the above-described aspects, the present disclosureprovides a manufacturing apparatus for a nano/micro structure network.

According to an exemplary embodiment, the manufacturing apparatus for anano/micro structure network may include: a first electrode and a secondelectrode extended in a first direction and separated from each other; asupport rod configured to connect one end of the first electrode to oneend of the second electrode; a rotation rod configured to be rotatedaround the first direction as a rotation axis and connected to thesupport rod; and a control unit configured to rotate the rotation rodafter applying a current between the first electrode and the secondelectrode, and apply a current between the first electrode and thesecond electrode after rotating the rotation rod.

According to an exemplary embodiment, even when the rotation rod isrotated, a distance between the first electrode and the second electrodeis uniformly maintained.

According to an exemplary embodiment, in a state where the firstelectrode and the second electrode are in contact with a first point ofa base layer including conductive structures and a second pointseparated from the first point, respectively, a current is appliedbetween the first electrode and the second electrode and the firstelectrode and the second electrode are rotated by the rotation rod, andin a state where the first electrode and the second electrode are incontact with a third point of the base layer and a fourth pointseparated from the third point, respectively, a current is appliedbetween the first electrode and the second electrode.

According to an exemplary embodiment, the manufacturing apparatus for anano/micro structure network may include: a support structure; aplurality of electrodes disposed adjacent to edges of the supportstructure; and a control unit configured to apply a current between afirst electrode and a second electrode selected from the plurality ofelectrodes, and apply a current between a third electrode and a fourthelectrode selected from the electrodes other than the first electrodeand the second electrode among the plurality of electrodes afterapplying the current between the first electrode and the secondelectrode.

According to an exemplary embodiment, in a state where the plurality ofelectrodes including the first to fourth electrodes is in contact withthe base layer including the conductive structures, a current is appliedbetween the first electrode and the second electrode and between thethird electrode and the fourth electrode.

According to an exemplary embodiment, the support structure includesfirst to fourth sides, and the plurality of electrodes is disposed alongthe first to fourth sides, respectively. The electrodes disposed alongthe first to fourth sides constitute first to fourth groups,respectively.

According to an exemplary embodiment, the first electrode and the secondelectrode are respectively included in different groups, and the thirdelectrode and the fourth electrode are respectively included indifferent groups.

Advantageous Effects

According to a substrate including nano/micro structures and a methodfor manufacturing the same in accordance with an exemplary embodiment ofthe present disclosure, a base solution is coated on nano/microstructures formed on an auxiliary substrate, and a base substrate isformed by performing a heat treatment to the base solution. Theauxiliary substrate is removed from the base substrate, so that a mainsurface of the base substrate adjacent to the auxiliary substrate isexposed. The main surface of the base substrate includes a portionincluding the nano/micro structures and may be substantially flat.Accordingly, it is possible to provide a substrate including nano/microstructures with a minimized surface roughness.

Further, according to a refining method and a refining apparatus for anano/micro structure in accordance with an exemplary embodiment of thepresent disclosure, a mixed solution including structures different fromeach other in mass and/or size is supplied and spread on a substrate andonly a part of the mixed solution is collected within a predetermineddistance range from a location at which the mixed solution is suppliedto the substrate. Structures having substantially the same mass and/orsize can be refined from the collected part of the mixed solution.

Furthermore, according to a manufacturing method and a manufacturingapparatus for a nano/micro structure network in accordance with anexemplary embodiment of the present disclosure, a plurality of currentpaths different from each other is provided to a base layer disposed ona substrate and including conductive structures, so that a plurality ofnetworks in which the structures are electrically connected may beformed. Accordingly, it is possible to provide a manufacturing methodand a manufacturing apparatus for a nano/micro structure network withminimize damage to the substrate, a minimized resistance of the baselayer, and substantially uniform sheet resistance.

DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart provided to explain a method for manufacturing asubstrate including nano/micro structures according to an exemplaryembodiment of the present disclosure.

FIG. 2A through FIG. 2F are diagrams provided to explain a substrateincluding nano/micro structures and a method for manufacturing the sameaccording to an exemplary embodiment of the present disclosure.

FIG. 3A and FIG. 3B are diagrams provided to explain a modificationexample of a metal nano wire substrate and a method for manufacturingthe same according to an exemplary embodiment of the present disclosure.

FIG. 4 is an SEM image of a substrate including nano/micro structuresaccording to an exemplary embodiment of the present disclosure.

FIG. 5 is a graph provided to explain a transmittance of a substrateincluding nano/micro structures according to an exemplary embodiment ofthe present disclosure.

FIG. 6 is an atomic force microscopic image provided to explain asurface roughness of a substrate including nano/micro structuresaccording to an exemplary embodiment of the present disclosure.

FIG. 7 through FIG. 11 are diagrams provided to explain a method forrefining a nano/micro structure according to an exemplary embodiment ofthe present disclosure.

FIG. 12 is a flowchart provided to explain a method for refining anano/micro structure according to an exemplary embodiment of the presentdisclosure.

FIG. 13 through FIG. 15 are diagrams provided to explain a method forrefining a nano/micro structure according to another exemplaryembodiment of the present disclosure.

FIG. 16 is a diagram provided to explain a refining apparatus for anano/micro structure according to an exemplary embodiment of the presentdisclosure.

FIG. 17 is a diagram provided to explain a refining apparatus for anano/micro structure according to another exemplary embodiment of thepresent disclosure.

FIG. 18 is a diagram provided to explain a refining apparatus for anano/micro structure according to yet another exemplary embodiment ofthe present disclosure.

FIG. 19 is a microscopic image of a spread experiment of structuresaccording to a method for refining a nano/micro structure in accordancewith an exemplary embodiment of the present disclosure.

FIG. 20 is a flowchart provided to explain a method for manufacturing anano/micro structure network according to an exemplary embodiment of thepresent disclosure.

FIG. 21 through FIG. 23 are perspective views provided to explain amethod for manufacturing a nano/micro structure network according to anexemplary embodiment of the present disclosure.

FIG. 24 is a diagram provided to explain a network formed betweencontact points of structures according to a method for manufacturing anano/micro structure network in accordance with an exemplary embodimentof the present disclosure.

FIG. 25 is a diagram provided to explain a manufacturing apparatus for anano/micro structure network according to an exemplary embodiment of thepresent disclosure.

FIG. 26 and FIG. 27 are diagrams provided to explain a manufacturingapparatus for a nano/micro structure network according to anotherexemplary embodiment of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.However, the technical concept of the present disclosure is not limitedto the exemplary embodiments described herein, but can be embodied invarious forms. The exemplary embodiments described herein are providedto complete disclosure of the present disclosure and convey the conceptof the present disclosure to a person having ordinary skill in the art.

In the present specification, in case where it is described that oneelement is on the other element, the one element may be directly formedon the other element or a third element may be intervened between them.Further, in the drawings, thicknesses of layers and areas areexaggerated for effective explanation of technical matters.

Although the terms “first”, “second”, “third”, and the like are used fordescribing various components in various exemplary embodiments, thesecomponents are not confined by these terms. These terms are merely usedfor distinguishing one component from the other components. Therefore, afirst component mentioned in any one exemplary embodiment may bementioned as a second component in another exemplary embodiment. Eachexemplary embodiment described and illustrated herein includescomplementary exemplary embodiments thereof Further, in the presentspecification, the term “and/or” is used to mean at least one of theassociated listed components is included.

A singular expression used herein includes a plural expression unless itis clearly construed in a different way in the context. The terms usedherein, such as “including” or “having”, are used only to designate thefeatures, numbers, steps, operations, constituent elements, orcombinations thereof described in the specification, but should not beconstrued to exclude existence or addition of one or more otherfeatures, numbers, steps, operations, constituent elements, orcombinations thereof. Further, the term “connection” used hereinincludes indirect connection and direction connection of a plurality ofcomponents.

Further, in the following description, a detailed explanation ofwell-known related functions or configurations may be omitted to avoidunnecessarily obscuring the subject matter of the present disclosure.

Furthermore, the term “nano/micro structure” used herein includes awire, a rod, fiber, a line, a flake, a particle, or the like, and aminute structure having a micro size or a nano size.

A substrate including nano/micro structures and a method formanufacturing the same according to an exemplary embodiment of thepresent disclosure will be described.

FIG. 1 is a flowchart provided to explain a method for manufacturing asubstrate including nano/micro structures according to an exemplaryembodiment of the present disclosure, and FIG. 2A through FIG. 2F arediagrams provided to explain a substrate including nano/micro structuresand a method for manufacturing the same according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 2A, an auxiliary substrate 100 is prepared. Theauxiliary substrate 100 may include a flat upper surface. The auxiliarysubstrate 100 may be a flexible substrate. The auxiliary substrate 100may be any one of a glass substrate, a silicon semiconductor substrate,a compound semiconductor substrate, or a polymer substrate. For example,the auxiliary substrate 100 may be any one of a PET substrate, a PCsubstrate, a PEN substrate, a PMMA substrate, a PU substrate, or a PIsubstrate.

A releasing layer 110 may be formed on the auxiliary substrate 100. Thereleasing layer 110 may be configured to easily remove the auxiliarysubstrate 100 from a base substrate to be described later. For example,the releasing layer 110 may be formed using a silicon-based releaseagent or a fluorine-based release agent.

Referring to FIG. 1 and FIG. 2B, nano/micro structures 120 may be formedon the upper surface of the auxiliary substrate 100 (S110). According toan exemplary embodiment, the nano/micro structures 120 may be formed ofa conductive material. For example, the nano/micro structures 120 may besilver (Ag) nano wires. The nano/micro structures 120 may be formed byvarious methods such as bar coating, spin coating, spray coating, dipcoating, brush coating, or gravure coating.

Before the nano/micro structures 120 are formed, a pretreatment processfor reducing surface energy of the upper surface of the auxiliarysubstrate 100 and/or an upper surface of the releasing layer 110 may beperformed to easily disperse the nano/micro structures 120 on the uppersurface of the auxiliary substrate 100. For example, a plasma processusing a gas such as oxygen, argon, nitrogen, or hydrogen may beperformed, or a UV or ozone process may be performed.

After the nano/micro structures 120 are formed, the auxiliary substrate100 on which the nano/micro structures 120 are formed may be dried toremove a solvent supplied onto the auxiliary substrate 100 while thenano/micro structures 120 are formed. For example, the auxiliarysubstrate 100 may be dried at a temperature of 60° C. to 80° C.

After the nano/micro structures 120 are formed, a heat treatment processmay be performed. The conductivity of the nano/micro structures 120 maybe improved by the heat treatment process. For example, the heattreatment process may be performed at 160° C. to 180° C.

A gap 120 a may be present between the nano/micro structures 120 and thereleasing layer 110 or between the nano/micro structures 120 and theauxiliary substrate 100 if the formation process of the releasing layer110 is omitted.

Referring to FIG. 1 and FIG. 2C, a base solution 130 may be coated onthe nano/micro structures 120 (S120). The base solution 130 may be in asolution state and may include a material of a flexible substrate. Forexample, the base solution 130 may include at least any one ofpolyethylene terephthalate (PET), polyethylene naphthalate (PEN),polycarbonate (PC), polyether sulfone (PES), polyimide (PI),poly(methylmethacrylate) (PMMA), or acrylite.

The base solution 130 may be formed by various methods such as barcoating, spin coating, spray coating, dip coating, brush coating, orgravure coating.

According to an exemplary embodiment, before the base solution 130 iscoated on the nano/micro structures 120, the nano/micro structures 120may be patterned.

Referring to FIG. 1 and FIG. 2D, a base substrate 132 covering thenano/micro structures 120 may be formed by curing the base solution 130through a heat treatment to the base solution 130 (S130). For example,the base solution 130 may be heat-treated at 70° C. to 300° C. Morespecifically, for example, if the base solution 130 is a PMMA solution,the base solution 130 may be heat-treated at 80° C. to 100° C.

While the base solution 130 is heat-treated, at least parts of thenano/micro structures 120 may be fused. Thus, parts of the nano/microstructures 120 adjacent to each other may be bonded 120 b and connectedto each other. Accordingly, the resistance of the nano/micro structures120 may be reduced.

Referring to FIG. 1 and FIG. 2E, the auxiliary substrate 100 and thereleasing layer 110 may be removed from the base substrate 132 (S140).The auxiliary substrate 100 and the releasing layer 110 are removed, sothat a main surface MS of the base substrate 132 may be exposed to theoutside.

The main surface MS of the base substrate 132 may be a surface adjacentto the upper surface of the auxiliary substrate 100. In other words, themain surface MS may be a surface in contact with the releasing layer 110or the auxiliary substrate 100 before the auxiliary substrate 100 andthe releasing layer 110 are removed. The base substrate 132 may includea counter surface facing the main surface MS.

As described above with reference to FIG. 2C, the base solution 130 issupplied onto the nano/micro structures 120 as being in a liquid state.The base solution in a liquid state may readily fill the gaps 120 abetween the releasing layer 110 and the nano/micro structures 120 orbetween the auxiliary substrate 100 and the nano/micro structures 120 ifthe formation process of the releasing layer 110 is omitted. Thus, themain surface MS of the base substrate 132 formed by converting the basesolution 130 into a solid state through a heat treatment may becomeflat.

The exposed main surface MS may include a first portion MS1 includingthe base substrate 132 and a second portion MS2 including the nano/microstructures 120. The first portion MS1 and the second portion MS2 mayconstitute one flat surface. A part of the base substrate 132constituting the first portion MS1 may be formed by performing a heattreatment to the base solution 130 filling the gap 120 a.

At least parts of the nano/micro structures 120 may include an exposedportion EP and a dent portion DP. The exposed portion EP may constitutethe second portion MS2 of the main surface MS. The dent portion DP maybe located under the first portion MS1 of the main surface MS.

The nano/micro structures 120 may be located within the base substrate132 so as to be relatively closer to the main surface MS than to thecounter surface.

The removing of the auxiliary substrate 100 and the releasing layer 110may include separating the auxiliary substrate 100 from the releasinglayer 110 and the base substrate 132, and removing the releasing layer110 from the base substrate 132 by dissolving the releasing layer 110with a solvent. Otherwise, the releasing layer 110 and the auxiliarylayer 100 may be removed from the base substrate 132 at the same time.

After the main surface MS is exposed by removing the auxiliary substrate100 and the releasing layer 110, the base substrate 132 may beheat-treated. Thus, the nano/micro structures 120 weakly bonded to eachother while the base substrate 132 is formed by performing a heattreatment to the base solution 130 may become strongly bonded to eachother.

Referring to FIG. 2F, after the main surface MS is exposed by removingthe auxiliary substrate 100 and the releasing layer 110, a conductivethin film 140 may be formed on the main surface MS. The conductive thinfilm 140 may include a conductive polymer (for example, PEDOT:PSS).

According to an exemplary embodiment of the present disclosure, the basesubstrate 132 is formed by performing a heat treatment to the basesolution 130 in a liquid state on the nano/micro structures 120 formedon the auxiliary substrate 100. Thus, the main surface MS of the basesubstrate 132 in contact with the auxiliary substrate 100 or thereleasing layer 110 may become flat although the main surface MSincludes the portion including the nano/micro structures 120.Accordingly, it is possible to suppress deterioration in property ofsemiconductor elements, such as a thin film transistor, and an organiclight emitting element, and the like formed on the main surface MS ofthe base substrate 132.

Generally, if metal nano wires are formed on a substrate, a surface ofthe substrate has a surface roughness of several hundred nm. Even if anorganic/inorganic thin film is formed on the surface of the substrate onwhich the metal nano wires are formed, the surface has a surfaceroughness of about 100 nm or more. If a semiconductor element is formedon the surface of the substrate having a high surface roughness,properties of the semiconductor element may deteriorate. For example, ifan organic light emitting element is formed on the surface of thesubstrate, there may occur non-uniformity in an internal electric fieldor a short circuit between an anode and a cathode. Accordingly, internaldegradation of the organic light emitting element may occur, resultingin a decrease in lifetime of the organic light emitting element.

However, as described above, according to an exemplary embodiment of thepresent disclosure, the semiconductor elements can be formed on thesubstrate having the main surface MS which includes the nano/microstructures 120 and is flat, and, thus, deterioration in property of thesemiconductor elements can be minimized.

In the above-described exemplary embodiment, other micro materials maybe formed on the auxiliary substrate 100 in addition to the nano/microstructures 120. Details thereof will be described with reference to FIG.3A and FIG. 3B.

FIG. 3A and FIG. 3B are diagrams provided to explain a modificationexample of a metal nano wire substrate and a method for manufacturingthe same according to an exemplary embodiment of the present disclosure.

Referring to FIG. 3A, the auxiliary substrate 100 and the releasinglayer 110 on the auxiliary substrate 100 are provided as described abovewith reference to FIG. 2A. The nano/micro structures 120 and a nanomaterial 122 may be formed on the releasing layer 110. The nano material122 may strengthen the connection between the nano/micro structures 120and improve the dispersity of the nano/micro structures 120.

According to an exemplary embodiment, before the nano/micro structures120 are formed on the auxiliary substrate as described above withreference to FIG. 2B, the nano material 122 is formed on the auxiliarysubstrate 100. After the nano material 122 is formed, the nano/microstructures 120 may be formed.

According to another exemplary embodiment unlike the above description,after the nano/micro structures 120 are formed on the auxiliarysubstrate 100 and before the base solution 130 is coated on theauxiliary substrate 100, the nano material 122 may be formed on theauxiliary substrate 100.

The nano material 122 may include a material different from thenano/micro structures 120. For example, the nano material 122 mayinclude at least any one of graphene flake, single-walled CNT,double-walled CNT, multi-walled CNT, C60, C85, or C70.

The nano material 122 may be formed together with a conductive organicmaterial on the auxiliary substrate 100. For example, the conductiveorganic material may include at least any one of PEDOT:PSS or PVP.

After the nano/micro structures 120 and the nano material 122 are formedon the auxiliary substrate 100, the base solution 130 may be coated onthe auxiliary substrate 100 as described above with reference to FIG.2C. After the base solution 130 is coated, the base solution 130 may beheat-treated to form the base substrate 132 as described above withreference to FIG. 2D. The base substrate 132 may cover the nano/microstructures 120 and the nano material 122.

Referring to FIG. 3B, the auxiliary substrate 100 and the releasinglayer 110 may be removed from the base substrate 132 as described abovewith reference to FIG. 2E. Thus, the main surface MS of the basesubstrate 132 in contact with the releasing layer 110 (the main surfacein contact with the auxiliary substrate 100 if the releasing layer 110is omitted) may be exposed.

The exposed main surface MS may include the first portion MS1 includingthe base substrate 132, the second portion MS2 including the nano/microstructures 120, and a third portion MS3 including the nano material 122.The first portion MS1, the second portion MS2, and the third portion MS3may constitute one flat surface.

As described with reference to FIG. 2F, a conductive thin film may befurther formed on the main surface MS of the base substrate 132.

According to a modification example of the substrate includingnano/micro structures and the method for manufacturing the sameaccording to an exemplary embodiment of the present disclosure, the nanomaterial 122 is formed on the auxiliary substrate 100 before or afterthe nano/micro structures 120 are formed. Thus, the bonding and thedispersity of the nano/micro structures can be improved.

Hereinafter, the results of a property evaluation of the substrateincluding nano/micro structures according to the above-describedexemplary embodiments of the present disclosure will be described.

FIG. 4 is an SEM image of a substrate including nano/micro structuresaccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 4, a silver nano wire is formed on an auxiliarysubstrate by bar-coating, and PMMA is formed on the silver nano wire bydrop-casting. FIG. 4A is an image showing a flat surface of the PMMAsubstrate including the silver nano wire, and FIG. 4B is an imageshowing an inclined surface of the PMMA including the silver nano wire.

As can be seen from FIG. 4, it is observed that silver nano wires aredistributed on the PMMA substrate at an adequate density. Further, it isobserved from FIG. 4B that the PMMA covers parts of silver nano wires.In other words, the PMMA covers a silver nano wires having a highsurface roughness and fills a space between the silver nano wires toreduce a surface roughness.

FIG. 5 is a graph provided to explain a transmittance of a substrateincluding nano/micro structures according to an exemplary embodiment ofthe present disclosure.

Referring to FIG. 5, the transmittance of PEDOT:PSS, which is aconductive polymer used as a hole injecting layer, a silver nano wire,and a laminated structure of a silver nano wire and PEDOT:PSS weremeasured. As can be seen from FIG. 5, the PEDOT:PSS has the highesttransmittance and the laminated structure of PEDOT:PSS on a silver nanowire has the lowest transmittance.

FIG. 6 is an atomic force microscopic image provided to explain asurface roughness of a substrate including nano/micro structuresaccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 6, according to an exemplary embodiment of the presentdisclosure, a silver nano wire was formed on a glass substrate, and aPMMA solution was coated on the silver nano wire and then heat-treatedto form a PMMA substrate.

Then, PMMA substrate including the silver nano wire was separated fromthe glass substrate and PEDOT:PSS was coated. A surface thereof wasmeasured with an atomic force microscope. Further, as a comparativeexample of the exemplary embodiment of the present disclosure, a silvernano wire was formed on a glass substrate and PEDOT:PSS was formed onthe silver nano wire. Then, a surface thereof was measured with theatomic force microscope.

FIG. 6A and FIG. 6B are atomic force microscopic images of a surface ofthe silver nano wire formed on the glass substrate and a surface of thelaminated structure of the silver nano wire and PEDOT:PES formed on theglass substrate, respectively, according to the comparative example ofthe present disclosure. FIG. 6C and FIG. 6D are atomic force microscopicimages of a surface of the silver nano wire transferred to the PMMAsubstrate and a surface of the laminated structure of PEDOT:PSS on thePMMA substrate including the silver nano wire, respectively, accordingto the exemplary embodiment of the present disclosure.

As can be seen from FIG. 6A, a peak-to-valley surface roughness of thesilver nano wire formed on the glass substrate according to thecomparative example of the present disclosure was about 210 nm. In otherwords, the surface roughness was about two to three times higher than 80nm, which is the thickness of the silver nano wire, due to overlaps ofsilver nano wires. Further, as can be seen from FIG. 6B, apeak-to-valley surface roughness was reduced to 50 nm, i.e. about ¼,through a process of coating PEDOT:PSS on the silver nano wire formed onthe glass substrate, but still had a high value.

Meanwhile, as can be seen from FIG. 6C, if the silver nano wire istransferred to the PMMA substrate according to the exemplary embodimentof the present disclosure, a peak-to-valley surface roughness was 62 nmwhich is considerably lower than that of FIG. 6A. Further, as can beseen from FIG. 6D, if PEDOT:PSS is coated on the PMMA substrateincluding the silver nano wire, a peak-to-valley surface roughness was26 nm which is considerably lower than that of FIG. 6B, and the surfaceroughness was reduced by about 74% on the basis of a root-mean-square(RMS) roughness.

It is confirmed that a method of supplying a PMMA solution onto a silvernano wire disposed on a glass substrate, performing a heat treatment tothe PMMA solution to form a PMMA film, removing the glass substrate andcoating the PMMA film including the silver nano wire with PEDOT:PSSaccording to an exemplary embodiment of the present disclosure is aneffective method for minimizing a surface roughness of a substrateincluding a silver nano wire.

A refining method and a refining apparatus for a nano/micro structureaccording to an exemplary embodiment of the present disclosure will bedescribed.

FIG. 7 through FIG. 11 are diagrams provided to explain a method forrefining a nano/micro structure according to an exemplary embodiment ofthe present disclosure, and FIG. 12 is a flowchart provided to explain amethod for refining a nano/micro structure according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 7, a substrate 200 is provided. The substrate 200 maybe a semiconductor substrate, a plastic substrate, or a glass substrate.The substrate 200 may be flexible.

A pretreatment 210 may be performed to the substrate 200. Due to thepretreatment 210 of the substrate 200, surface energy of the substratemay be reduced. According to an exemplary embodiment, the pretreatment210 of the substrate 200 may include supplying at least any one ofplasma, UV (ultra violet), or ozone to an upper surface of the substrate200. For example, plasma using oxygen (O), argon (Ar), nitrogen (N), orhydrogen (H) gas may be supplied to the upper surface of the substrate200.

Referring to FIG. 8, a peeling layer 220 may be coated on the uppersurface of the substrate 200. As described below, the peeling layer 220is configured to easily separate a mixed solution including structuresto be formed on the peeling layer 220 from the substrate 200.

The peeling layer 220 may be coated by any one method of bar coating,spray coating, brush coating, or gravure coating. The peeling layer 220may include a polymer material. For example, the peeling layer 220 maybe formed of at least any one of polymethylmethacrylate,polyvinylpyrrolidone, polyethylene terephthalate, polystyrene,polyvinylchloride, polycarbonate, or polyimide. Otherwise, the peelinglayer 220 may include a complex of the above-described polymer materialand an inorganic material. For example, the inorganic material mayinclude at least any one of Au, Si, Ag, Cu, Ni, Al, Sn, C, SiO2, ZnO,Al2O3, In2O3, or SnO2.

After the peeling layer 220 is coated, a heat treatment or plasmatreatment 230 may be performed to the peeling layer 220. Thus, the mixedsolution including the structures can be easily spread on the peelinglayer 220.

Referring to FIG. 9 and FIG. 12, a mixed solution 240 includingstructures 242 different from each other in mass is prepared (S210).According to an exemplary embodiment, the structures 242 may be silvernano structures such as silver nano particles and silver nano wires.

According to another exemplary embodiment, the structures 242 mayinclude at least any one of inorganic materials (for example, grapheneflake, single-walled CNT, double-walled CNT, multi-walled CNT, C60, C85,C70, and the like), metal nano particles (for example, Au, Ag, Cu, Ni,Al, and the like), semiconductor materials (for example, Si, C, GaAs,ZnSe, InP, CdS, and the like), semiconductor oxide materials (SiO2, ZnO,Al2O3, In2O3, SnO2, and the like), semiconductor quantum dot materials(for example, CdSe/CdSe, CdSe/ZnTe, ZnSe/ZnS, PbS/CdS, ZnS/CdSe,CdS/ZnS, and the like) in the form of core/shell, or semiconductor nanowire materials (for example, ZnO/ZnS, AlP/AlN, AlN/AlAs, and the like)in the form of core/shell. In addition to the above-described examples,the structures 242 may include other materials.

The mixed solution 240 including the structures 242 is supplied onto theupper surface of the substrate 200, so that the mixed solution 240including the structures 242 may be spread on the peeling layer 220(S220). According to an exemplary embodiment, the mixed solution 240 maybe supplied onto the substrate 200 so as not to cover the entire uppersurface of the peeling layer 220. For example, if a mixed solution issupplied onto a substrate having a size of 25×25 mm2, the mixed solutionof about 10 μl to 15 μl may be supplied.

Among the structures 242 included in the mixed solution 240 suppliedonto the substrate 200, the structures 242 having relatively small masscan be spread farther from a location 240P where the mixed solution 240is supplied to the substrate 200 than the structures 242 havingrelatively great mass. In other words, as the structure 242 is closer tothe location 240P where the mixed solution 240 is supplied to thesubstrate 200, the structure 242 may have a greater mass and/or size.Further, as the structure 240 is farther from the location 240P wherethe mixed solution 240 is supplied to the substrate 200, the structure242 may have a smaller mass and/or size. For example, if the structure242 is a silver nano structure including a silver nano particle and asilver nano wire, a relatively long silver nano wire may be disposed inan area close to the location 240P where the mixed solution 240 issupplied to the substrate 200 and a relatively short silver nano wire ora silver nano particle may be disposed in an area far from the location240P where the mixed solution 240 is supplied to the substrate 200.

According to an exemplary embodiment, the process of supplying the mixedsolution 240 onto the substrate 200 and spreading the mixed solution 240may include a process of drying the mixed solution 240. In other words,after the mixed solution 240 is completely spread on the substrate 200and before the structures 242 are randomly disposed within the mixedsolution 240, the mixed solution 240 may be dried, so that randomdisposal of the structures 242 can be suppressed. For example, the mixedsolution 240 may be dried by applying heat to the mixed solution 240.

Referring to FIG. 10 through FIG. 12, a part of the mixed solution 240spread on the substrate 200 may be collected (S230). The collected partof the mixed solution 240 may be located within a predetermined distancerange D1 to D2 from the location 240P where the mixed solution 240 issupplied to the substrate 200. In a plain view, the part of the mixedsolution 240 located within the predetermined distance range D1 to D2from the location 240P where the mixed solution 240 is supplied to thesubstrate 200 may have a doughnut shape. The structures 242 included inthe remaining part of the mixed solution 240 may have substantially thesame mass and/or size.

The process of collecting of the part of the mixed solution 240 mayinclude removing the rest of the mixed solution 240 located out of thepredetermined distance range D1 to D2 from the location 240P where themixed solution 240 is supplied to the substrate 200 and collecting theremaining part of the mixed solution 240. According to an exemplaryembodiment, the rest of the mixed solution 240 may be removed by aphysical method.

The structures 242 included in the collected part of the mixed solution240 may be recovered from the part of the mixed solution 240 (S240). Theprocess of recovering the structures 242 from the part of the mixedsolution 240 may include supplying a solution 250 that dissolves theremaining part of the mixed solution 240 and the peeling layer 220 onthe substrate 200 and recovering the structures 242 from the solution250 including the structures 242 included in the remaining part of themixed solution 240. According to an exemplary embodiment, the process ofrecovering the structures 242 may include recovering the structures 242from the solution 250 in which the part of the mixed solution 240 isdissolved, with a centrifuge.

According to an exemplary embodiment of the present disclosure, a mixedsolution including structures different from each other in mass issupplied onto a substrate and spread on the substrate, and only a partof the mixed solution located within a predetermined distance range froma location where the mixed solution is supplied is collected. Thus,structures having substantially the same mass and/or size can be refinedfrom the collected part of the mixed solution through a simple process.

If structures having substantially the same mass and/or size are refinedfrom structures different from each other in mass and/or size using afilter or a centrifuge without the spreading process according to anexemplary embodiment of the present disclosure, the structures may bedeformed or cut during the refining process.

However, as described above, according to an exemplary embodiment of thepresent disclosure, if structures having substantially the same massand/or size are refined using a difference in degree of spread dependingon the mass, a refining method of a nano/micro structure with minimizeddeformation and cutting of the structures and an improved productionyield can be provided.

FIG. 7 through FIG. 11 illustrate that a mixed solution is supplied to asubstrate including an upper surface in parallel to the ground. However,according to another exemplary embodiment of the present disclosure, theupper surface of the substrate to which the mixed solution is suppliedmay be inclined to the ground. Details thereof will be described withreference to FIG. 13 through FIG. 15.

FIG. 13 through FIG. 15 are diagrams provided to explain a method forrefining a nano/micro structure according to another exemplaryembodiment of the present disclosure.

Referring to FIG. 13, a substrate 205 and a supporting table 201 thatsupports the substrate 205 are provided. The substrate 205 may be of thesame kind as the substrate 200 described above with reference to FIG. 7.The substrate 205 may be extended in a direction to be adjacent to theground.

An upper surface 104 of the substrate 205 may be not parallel butinclined to the ground due to the supporting table 201. FIG. 13illustrates that the supporting table 201 and the substrate 205 areseparate components. However, the supporting table 201 and the substrate205 may be formed as one body.

As described above with reference to FIG. 7, a pretreatment may beperformed to the upper surface 104 of the substrate 205 using at leastany one of plasma, UV (ultra violet), or ozone.

Referring to FIG. 14, a peeling layer 222 may be formed on the substrate205. Since the peeling layer 222 is conformal in thickness, an uppersurface of the peeling layer 222 may also be inclined to the ground inthe same manner as the upper surface 104 of the substrate 205. Thepeeling layer 222 may be extended in a direction to be adjacent to theground. The peeling layer 222 may be formed by the method describedabove with reference to FIG. 8.

Referring to FIG. 15, the mixed solution 240 including structures may beprepared as described above with reference to FIG. 9. The mixed solution240 may be supplied onto the upper surface of the peeling layer 222inclined to the ground. A location 240P where the mixed solution 240 issupplied to the substrate 205 may be higher than the ground. Thus, themixed solution 240 may be spread on the peeling layer 222 toward theground. Since the mixed solution 240 is supplied onto the upper surfaceof the peeling layer 222/the upper surface of the substrate 205 inclinedto the ground, the mixed solution 240 can be easily spread. The processof spreading the mixed solution 240 may include a process of drying themixed solution as described above with reference to FIG. 9.

As described above with reference to FIG. 9, among the structuresincluded in the mixed solution 240, the structures having relativelysmall mass can be spread farther from the location 240P where the mixedsolution 240 is supplied onto the substrate 205 than the structureshaving relatively great mass. That is, the structures having relativelysmall mass and/or size may be disposed adjacent to the ground and thestructures having relatively great mass and/or size may be disposed farfrom the ground.

Then, as described above with reference to FIG. 10 through FIG. 12, apart 240A of the mixed solution 240 located within predetermineddistance range from the location 240P where the mixed solution 240 issupplied onto the substrate 205 is collected. Thus, the structureshaving substantially the same mass and/or size can be refined.

A refining apparatus for a nano/micro structure to which the method forrefining a nano/micro structure according to the above-describedexemplary embodiment of the present disclosure will be described withreference to FIG. 16 through FIG. 18.

FIG. 16 is a diagram provided to explain a refining apparatus for anano/micro structure according to an exemplary embodiment of the presentdisclosure.

Referring to FIG. 16, a refining apparatus for a nano/micro structureaccording to an exemplary embodiment of the present disclosure mayinclude the substrate 205, a mixed solution supply unit 310, a substratepretreatment supply unit 320, and an inclination adjusting unit 330.

The substrate 205 may include an upper surface inclined to the ground asdescribed above with reference to FIG. 13. The substrate 205 may besupported on a supporting table 202. FIG. 16 illustrates that thesupporting table 202 and the substrate 205 are separate components.However, the supporting table 202 and the substrate 205 may be formed asone body.

The mixed solution supply unit 310 may supply a mixed solution includingstructures different from each other in mass onto the upper surface ofthe substrate 205, as described above with reference to FIG. 9. Themixed solution supply unit 310 may supply the mixed solution onto a partof the upper surface of the substrate 205 placed at a relatively highlocation from the ground.

According to an exemplary embodiment, the mixed solution supply unit 310may drop the mixed solution to one point of the upper surface of thesubstrate 205. According to another exemplary embodiment, the mixedsolution supply unit 310 may supply the mixed solution to the uppersurface of the substrate 205 in the form of a line extended in onedirection. The one direction may intersect with an extension directionof the upper surface of the substrate 205 toward the ground.

The substrate pretreatment supply unit 320 may supply at least any oneof plasma, UV (ultra violet), or ozone to the upper surface of thesubstrate 205, as described above with reference to FIG. 1, in order toperform a pretreatment to the upper surface of the substrate 205.

The inclination adjusting unit 330 may adjust an inclination between theupper surface of the substrate 205 and the ground. For example, theinclination adjusting unit 330 may be a lifting device provided betweenthe supporting table 202 and the substrate 205. FIG. 16 illustrates thatthe inclination adjusting unit 330 adjusts a height of a part of thesubstrate 205 adjacent to the ground to adjust an inclination betweenthe upper surface of the substrate 205 and the ground. However, theinclination adjusting unit 330 may adjust a height of a part of thesubstrate 205 placed at a relatively high location from the ground toadjust an inclination between the upper surface of the substrate 205 andthe ground.

According to an exemplary embodiment, the inclination adjusting unit 330may maintain an inclination between the upper surface of the substrate205 and the ground at a predetermined angle while the mixed solution issupplied onto the upper surface of the substrate 205. According toanother exemplary embodiment, the inclination adjusting unit 330 maychange an inclination between the upper surface of the substrate 205 andthe ground while the mixed solution is supplied onto the upper surfaceof the substrate 205.

Unlike the illustration in FIG. 16, a plurality of substrates eachincluding an upper surface inclined to the ground may be provided.Details thereof will be described with reference to FIG. 17 and FIG. 18.

FIG. 17 is a diagram provided to explain a refining apparatus for anano/micro structure according to another exemplary embodiment of thepresent disclosure.

Referring to FIG. 17, the substrate 205 including the upper surfaceinclined to the ground illustrated with reference to FIG. 16 may beprovided plural in number. Parts of the upper surfaces of the pluralityof substrates 205 placed at a relatively high location from the groundmay be disposed to be adjacent to each other. Therefore, the singlemixed solution supply unit 310 can easily supply the mixed solution tothe upper surfaces of the plurality of substrates 205. Thus, nano/microstructures can be continuously refined.

FIG. 17 illustrates that the single mixed solution supply unit 310 isprovided. However, two or more mixed solution supply units may beprovided.

Unlike the illustration in FIG. 16 and FIG. 17, an upper surface of asubstrate may be increased in size as being closer to the ground.Details thereof will be described with reference to FIG. 18.

FIG. 18 is a diagram provided to explain a refining apparatus for anano/micro structure according to yet another exemplary embodiment ofthe present disclosure.

Referring to FIG. 18, unlike the illustration with reference to FIG. 17,upper surfaces of the plurality of substrates 205 a supported on aplurality of supporting tables 205 a may be gradually increased in sizeas being closer to the ground. In other words, a part of the uppersurface of the substrate 205 a located relatively adjacent to the groundmay be wider than a part of the upper surface of the substrate 205 alocated relatively far from the ground. Thus, a part of a mixed solutionspread on the upper surface of the substrate 205 a can be easilycollected.

Upper surfaces of the plurality of supporting tables 205 a that supportthe plurality of substrates 205 a may also be gradually increased insize as being closer to the ground, in the same manner as the uppersurfaces of the plurality of substrates 205 a.

Hereinafter, the results of a spread experiment of structures accordingto a method for refining a nano/micro structure in accordance with anexemplary embodiment of the present disclosure will be described.

FIG. 19 is a microscopic image of a spread experiment of structuresaccording to a method for refining a nano/micro structure in accordancewith an exemplary embodiment of the present disclosure.

Referring to FIGS. 19, 10 μl to 15 μl of methanol including silver nanowires was supplied onto a glass substrate having a size of 25×25 mm2 bydrop-casting. It can be seen that the silver nano wires are spreaddepending on the mass from a central portion of the glass substrate towhich the methanol including the silver nano wires is supplied.

Specifically, it was observed that an area (a) adjacent to the centralportion of the glass substrate to which the methanol is suppliedincludes a small number of silver nano wires of 30 μm or more, andsilver nano wires and silver nano particles of 5 μm to 15 μm. It wasobserved that an area (b) includes silver nano wires of about 30 win ata relatively high density and also includes a considerable number ofsilver nano particles. Further, it was observed that an area (c)includes silver nano wires of about 30 μm at the highest density.Furthermore, it was observed that areas (d) and (e) mostly includesilver nano wires of 10 μm or less and silver nano particles.

That is, it was observed that the silver nano wires have various degreesof spread depending on the mass, and, thus, it can be seen thatnano/micro structures having substantially the same size can be selectedand refined using a difference in degree of spread depending on the massof a nano/micro structure.

A manufacturing method and a manufacturing apparatus for a nano/microstructure network according to an exemplary embodiment of the presentdisclosure will be described.

FIG. 20 is a flowchart provided to explain a method for manufacturing anano/micro structure network according to an exemplary embodiment of thepresent disclosure, FIG. 21 through FIG. 23 are perspective viewsprovided to explain a method for manufacturing a nano/micro structurenetwork according to an exemplary embodiment of the present disclosure,and FIG. 24 is a diagram provided to explain a network formed betweencontact points of structures according to a method for manufacturing anano/micro structure network in accordance with an exemplary embodimentof the present disclosure.

Referring to FIG. 20 and FIG. 21, a base layer 410 may be formed on asubstrate 400 (S410).

The substrate 400 may be a semiconductor substrate, a plastic substrate,and/or a glass substrate. The substrate 400 may be flexible. Forexample, the substrate 400 may include any one of a glass substrate,polyethylene terephthalate (PET), polyethylene naphthalate (PEN),polycarbonate (PC), polyether sulfone (PES), polyimide (PI), oracrylite.

The base layer 410 may include a plurality of conductive structures.According to an exemplary embodiment, the structures may be silver nanostructures such as silver nano particles and silver nano wires.

According to another exemplary embodiment, the structures in the baselayer 410 may include at least any one of inorganic materials (forexample, graphene flake, single-walled CNT, double-walled CNT,multi-walled CNT, C60, C85, C70, and the like), metal nano particles(for example, Au, Ag, Cu, Ni, Al, and the like), semiconductor materials(for example, Si, C, GaAs, ZnSe, InP, CdS, and the like), conductiveorganic materials (for example, PEDOT:PSS, PVP, and the like),semiconductor oxide materials (SiO2, ZnO, Al2O3, In2O3, SnO2, and thelike), semiconductor quantum dot materials (for example, CdSe/CdSe,CdSe/ZnTe, ZnSe/ZnS, PbS/CdS, ZnS/CdSe, CdS/ZnS, and the like) in theform of core/shell, or semiconductor nano wire materials (for example,ZnO/ZnS, AlP/AlN, AlN/AlAs, and the like) in the form of core/shell inaddition to the silver nano structures.

The process of forming the base layer 410 including the structures onthe substrate 400 may be performed by bar coating, spray coating, spincoating, brush coating, dip coating, gravure coating, or the like.

Before the base layer 410 is formed on the substrate 400, a pretreatmentmay be performed to an upper surface of the substrate 400. Due to thepretreatment of the substrate 400, surface energy of the substrate 400may be reduced. According to an exemplary embodiment, the pretreatmentof the substrate 400 may include supplying at least any one of plasma,UV (ultra violet), or ozone to the upper surface of the substrate 400.For example, plasma using oxygen (O), argon (Ar), nitrogen (N), orhydrogen (H) gas may be supplied to the upper surface of the substrate400.

A first point P1 and a second point P2 different from the first point P1of the base layer 410 may be selected. The first point P1 and the secondpoint P2 may be any points on the base layer 410. For example, the firstpoint P1 and the second point P2 may be points adjacent to edges of thebase layer 410.

By applying a current between the first point P1 and the second pointP2, a first network 421 in which the first point P1 and the second pointP2 are electrically connected by the structures may be formed (S420).The first network 421 in which the first point P1 and the second pointP2 are electrically connected may substantially correspond to a currentpath flowing between the first point P1 and the second point P2.

Joule heat is generated by the current flowing between the first pointP1 and the second point P2. As illustrated in FIG. 5, a current junctionmay be formed by the joule heat at a contact point 415 a where thestructures 415 within the base layer 410 intersect with each other. Thatis, the contact point 415 a where the structures 415 disposed adjacentto the current path intersect with each other has a relatively highresistance. Accordingly, the joule heat may be generated at the contactpoint 415 a of the structures 415 by a current flowing between the firstpoint P1 and the second point P2. Due to the joule heat, atomsconstituting the structures 415 are moved, so that the structures 415separated from each other may be directly connected to each other or adistance between the structures 415 separated from each other may bereduced. Accordingly, the resistance at the contact point 415 a of thestructures 415 may be reduced, and the first network 421 in which thefirst point P1 and the second point P2 are electrically connected may beformed.

For example, if the structures 415 are silver nano structures, jouleheat may be generated at a contact point where the silver nanostructures intersect with each other by the current flowing between thefirst point P1 and the second point P2. Due to the joule heat, silveratoms constituting the silver nano structures are moved through apolymer material surrounding the silver nano structures, so that thesilver nano structures separated from each other may be connected toeach other.

Referring to FIG. 20 and FIG. 21, after the first network 421 is formed,a third point P3 and a fourth point P4 of the base layer 410 may beselected. The third point P3 and the fourth point P4 may be any pointsdifferent from the first point P1 and the second point P2. For example,the third point P3 and the fourth point P4 may be points adjacent toedges of the base layer 410.

By applying a current between the third point P3 and the fourth pointP4, a second network 422 in which the third point P3 and the fourthpoint P4 are electrically connected by the structures may be formed(S430). The second network 422 in which the third point P3 and thefourth point P4 are electrically connected may substantially correspondto a current path flowing between the third point P3 and the fourthpoint P4. The current path flowing between the third point P3 and thefourth point P4 may be different from the current path flowing betweenthe first point P1 and the second point P2.

Joule heat is generated by the current flowing between the third pointP3 and the fourth point P4. As illustrated in FIG. 5, the structures 415adjacent to the current path flowing between the third point P3 and thefourth point P4 may be electrically connected to each other by the jouleheat.

Referring to FIG. 4, after the first and second networks 421 and 422 areformed, a current may be applied between points other than the first tofourth points P1 to P4, so that a plurality networks 420 electricallyconnected by the structures may be further formed.

According to an exemplary embodiment of the present disclosure, the baselayer 410 including conductive structures is formed on the substrate400, and then, a plurality of processes of applying a current betweenany two points of the base layer 410 may be performed. Accordingly, aplurality of current paths different from each other may be provided inthe base layer 410 and a plurality of networks different from each othermay be formed so as to correspond to the plurality of current pathsdifferent from each other. Since the network in which the structures ofthe base layer 410 are electrically connected is formed, a resistance ofthe base layer 410 can be reduced. Further, since the plurality ofnetworks is provided, a sheet resistance of the base layer 410 may besubstantially uniform.

If the formation process of the network is omitted unlike theabove-described exemplary embodiment of the present disclosure, theresistance may be increased due to a polymer/insulation material presentbetween the structures. Further, if a heat treatment is performed to thestructures to reduce the resistance, the substrate may be damaged.

However, as described above, according to an exemplary embodiment of thepresent disclosure, a plurality of current paths different from eachother may be provided, so that a plurality of networks in which thestructures are electrically connected may be formed. Accordingly, it ispossible to provide a method for manufacturing a nano/micro structurewith minimized damage to a substrate and a minimized resistance and asubstantially uniform sheet resistance of the base layer 410.

Hereinafter, a manufacturing apparatus for manufacturing a nano/microstructure according to the above-described method for manufacturing anano/micro structure will be described.

FIG. 25 is a diagram provided to explain a manufacturing apparatus for anano/micro structure network according to an exemplary embodiment of thepresent disclosure.

Referring to FIG. 25, a manufacturing apparatus for a nano/microstructure network according to an exemplary embodiment of the presentdisclosure includes a support structure 510, a plurality of electrodes521, 522, 523, and 524 disposed adjacent to edges of the supportstructure 510, and a control unit 550 that controls the plurality ofelectrodes 521, 522, 523, and 524.

The support structure 510 may be disposed on the substrate 400 describedwith reference to FIG. 21 through FIG. 23 and the base layer 410disposed on the substrate 400 and including the conductive structures.The support structures 510 may include first to fourth sides. Accordingto an exemplary embodiment, a size of the support structure 510 may besimilar to that of the base layer 410. The support structure 510 may beformed of an insulation material.

The plurality of electrodes 521, 522, 523, and 524 may include a firstgroup 521 disposed along the first side of the support structure 510, asecond group 522 disposed along the second side of the support structure510, a third group 523 disposed along the third side of the supportstructure 510, and a fourth group 524 disposed along the fourth side ofthe support structure 510. According to an exemplary embodiment, theplurality of electrodes 521, 522, 523, and 524 may be disposed adjacentto the edges of the support structure 510 and thus may correspond to theedges of the base layer 410.

FIG. 6 illustrates that four or five electrodes are disposed along eachside of the support structure 510. However, the number of the electrodesmay be three or less, or six or more.

In a state where the plurality of electrodes 521, 522, 523, and 524 isin contact with the base layer 410, the control unit 550 may apply acurrent between first and second electrodes selected from the pluralityof electrodes 521, 522, 523, and 524. According to an exemplaryembodiment, the first and second electrodes may be included in differentgroups. For example, the first electrode may be included in the firstgroup 521 and the second electrode may be included in the third group523. Due to the current applied between the first electrode and thesecond electrode, a current may flow between a first point of the baselayer 410 in contact with the first electrode and a second point of thebase layer 410 in contact with the second electrode. Due to the currentflowing between the first point and the second point, a first network inwhich the first point and the second point are electrically connected bythe structures may be formed, as described above with reference to FIG.20 through FIG. 24.

After the first network is formed, in a state where the plurality ofelectrodes 521, 522, 523, and 524 is in contact with the base layer 410,the control unit 550 may apply a current between third and fourthelectrodes from the electrodes other than the first electrode and thesecond electrode among the plurality of electrodes 521, 522, 523, and524. According to an exemplary embodiment, the third and fourthelectrodes may be included in different groups. For example, the thirdelectrode may be included in the second group 522 and the fourthelectrode may be included in the fourth group 524. Due to the currentapplied between the third electrode and the fourth electrode, a currentmay flow between a third point of the base layer 410 in contact with thethird electrode and a fourth point of the base layer 410 in contact withthe fourth electrode. Due to the current flowing between the third pointand the fourth point, a second network in which the third point and thefourth point are electrically connected by the structures may be formed,as described above with reference to FIG. 20 through FIG. 24.

According to an exemplary embodiment, a magnitude of the current and/oran application time of the current applied between the first electrodeand the second electrode for forming the first network may besubstantially the same as a magnitude of the current and/or anapplication time of the current applied between the third electrode andthe fourth electrode for forming the second network.

By repeating the process of forming the first network and the process offorming the second network, the method for manufacturing a nano/microstructure network described with reference to FIG. 20 through FIG. 24can be performed by the manufacturing apparatus for a nano/microstructure network according to an exemplary embodiment of the presentdisclosure.

FIG. 26 and FIG. 27 are diagrams provided to explain a manufacturingapparatus for a nano/micro structure network according to anotherexemplary embodiment of the present disclosure.

Referring to FIG. 26, a manufacturing apparatus for a nano/microstructure network according to another exemplary embodiment of thepresent disclosure may include a first electrode 610, a second electrode620 separated from the first electrode 610, a support rod 630, arotation rod 640, and a control unit 650 that controls the firstelectrode 610, the second electrode 620, and the rotation rod 640. Themanufacturing apparatus for a nano/micro structure network according toanother exemplary embodiment of the present disclosure may be disposedon the substrate 400 described above with reference to FIG. 21 throughFIG. 23 and the base layer 410 disposed on the substrate 400 andincluding the conductive structures.

The first electrode 610 and the second electrode 620 may be separatedfrom each other and extended in a first direction. The first directionmay be a direction perpendicular to the upper surface of the base layer410. According to an exemplary embodiment, a length of the firstelectrode 610 may be substantially the same as that of the secondelectrode 620.

One end of the first electrode 610 and one end of the second electrode620 may be respectively connected to both ends of the support rod 630.According to an exemplary embodiment, the first electrode 610 and thesecond electrode 620 may be fixed to the support rod 630.

The rotation rod 640 may be connected to a central portion of thesupport rod 630 and extended in the first direction. The rotation rod640 may be rotated around the first direction as a rotation axis.Accordingly, the support rod 630 may be rotated around the rotation rod640 as a rotation axis, and the first electrode 610 and the secondelectrode 620 connected to the both ends of the support rod 630 may berotated. The first electrode 610 and the second electrode 620 may befixed to the both ends of the support rod 630. Thus, even if therotation rod 640 is rotated, a distance between the first electrode 610and the second electrode 620 may be uniformly maintained.

In a state where the other ends of the first electrode 610 and thesecond electrode 620 are in contact with the base layer 410, the controlunit 650 may apply a current between the first electrode 610 and thesecond electrode 620. Due to the current applied between the firstelectrode 610 and the second electrode 620, a current may flow between afirst point of the base layer 410 in contact with the first electrode610 and a second point of the base layer 410 in contact with the secondelectrode 620. According to an exemplary embodiment, the first point andthe second point may be adjacent to the edges of the base layer 410. Dueto the current flowing between the first point and the second point, afirst network 661 in which the first point and the second point areelectrically connected by the structures may be formed, as describedabove with reference to FIG. 20 through FIG. 24.

After the first network 661 is formed, the control unit 650 may rotatethe rotation rod 640. Accordingly, the first electrode 610 and thesecond electrode 620 may be respectively brought into contact with athird point and a fourth point of the base layer 410. As describedabove, even if the rotation rod 640 is rotated, a distance between thefirst electrode 610 and the second electrode 620 is uniformlymaintained. Thus, a distance between the first point and the secondpoint may be substantially the same as a distance between the thirdpoint and the fourth point.

In a state where the other ends of the first electrode 610 and thesecond electrode 620 are in contact with the third point and the fourthpoint of the base layer 410, the control unit 650 may apply a currentbetween the first electrode 610 and the second electrode 620. Due to thecurrent applied between the first electrode 610 and the second electrode620, a current may flow between the third point and the fourth point.Due to the current flowing between the third point and the fourth point,a second network 662 in which the third point and the fourth point areelectrically connected by the structures may be formed, as describedabove with reference to FIG. 20 through FIG. 24.

According to an exemplary embodiment, a magnitude of the current and/oran application time of the current applied between the first electrode610 and the second electrode 620 for forming the first network 661 maybe substantially the same as a magnitude of the current and/or anapplication time of the current applied between the first electrode 610and the second electrode 620 for forming the second network 662.Further, as described above, since the distances between the pointsbetween which a current is applied by the first electrode 610 and thesecond electrode 620 are the same, a difference in length between aplurality of networks formed by the current applied by the firstelectrode 610 and the second electrode 620 can be minimized. Therefore,the uniformity in sheet resistance of the base layer 410 can beimproved.

By repeating the process of forming the first network 661 and theprocess of forming the second network 662, the method for manufacturinga nano/micro structure described with reference to FIG. 20 through FIG.24 can be performed by the manufacturing apparatus for a nano/microstructure according to an exemplary embodiment of the presentdisclosure.

Although the present disclosure has been described in detail withreference to the exemplary embodiments, the scope of the presentdisclosure is not limited to specific exemplary embodiments but shouldbe construed based on the following claims. Further, it would beunderstood by a person having ordinary skill in the art that variouschanges and modifications can be made without departing from the scopeof the present disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a substrate, a method formanufacturing the same, a method for refining a nano/micro structure, amethod for manufacturing a nano/micro structure network, and amanufacturing apparatus therefor and is applied to technologies ofvarious fields such as organic light emitting elements, liquid crystaldisplays, touch panels, or solar cells, etc.

1. A method for manufacturing a substrate including nano/microstructures, comprising: forming nano/micro structures on an uppersurface of an auxiliary substrate; coating a base solution on thenano/micro structures; forming a base substrate covering the nano/microstructures by performing a heat treatment to the base solution; andremoving the auxiliary substrate from the base substrate.
 2. The methodfor manufacturing a substrate including nano/micro structures of claim1, wherein the base solution fills gaps between the nano/microstructures and the auxiliary substrate.
 3. The method for manufacturinga substrate including nano/micro structures of claim 1, furthercomprising: performing a pretreatment process for reducing surfaceenergy of the upper surface of the auxiliary substrate before formingthe nano/micro structures on the auxiliary substrate.
 4. The method formanufacturing a substrate including nano/micro structures of claim 1,further comprising: forming a releasing layer on the upper surface ofthe auxiliary substrate before forming the nano/micro structures,wherein the nano/micro structures are formed on the releasing layer, andthe separating of the auxiliary substrate from the base substrateincludes removing the releasing layer.
 5. The method for manufacturing asubstrate including nano/micro structures of claim 1, wherein theauxiliary substrate is removed from the base substrate to expose a mainsurface of the base substrate adjacent to the upper surface of theauxiliary substrate.
 6. The method for manufacturing a substrateincluding nano/micro structures of claim 5, further comprising: forminga conductive film on the main surface of the base substrate.
 7. Themethod for manufacturing a substrate including nano/micro structures ofclaim 4, wherein the releasing layer is formed using a silicon-basedrelease agent or a fluorine-based release agent.
 8. The method formanufacturing a substrate including nano/micro structures of claim 1,further comprising: performing a heat treatment process for improvingthe conductivity of the nano/micro structures before the coating thebase solution on the nano/micro structures.
 9. The method formanufacturing a substrate including nano/micro structures of claim 1,wherein the forming the base substrate comprises fusing at least partsof the nano/micro structures for reducing the resistance of thenano/micro structures.
 10. The method for manufacturing a substrateincluding nano/micro structures of claim 9, wherein parts of thenano/micro structures adjacent to each other are bonded and connected toeach other.
 11. The method for manufacturing a substrate includingnano/micro structures of claim 10, wherein parts of the nano/microstructures adjacent to each other are bonded and connected to eachother.
 12. The method for manufacturing a substrate including nano/microstructures of claim 5, wherein the main surface of the base substrate afirst portion including the base substrate and a second portionincluding the nano/micro structures.
 13. The method for manufacturing asubstrate including nano/micro structures of claim 12, wherein the firstportion and the second portion of the main surface constitute one flatsurface the main surface.
 14. The method for manufacturing a substrateincluding nano/micro structures of claim 5, further comprising:performing a heat treatment process to the base substrate for improvingthe bondability of the nano/micro structures after the main surface isexposed.
 15. The method for manufacturing a substrate includingnano/micro structures of claim 1, further comprising: refining thenano/micro structures before forming the nano/micro structures, whereinthe refining the nano/micro structures comprises: preparing a mixedsolution including the nano/micro structures with different dimensions;spreading the mixed solution including the nano/micro structures on asubstrate that is inclined to form a layer on the substrate includingsubsets of nano/micro structures each having nano/micro structures withsubstantially same mass or size; collecting a part of the layer on thesubstrate, the part of the layer including at least one subset of thenano/micro structures; and recovering the subset of nano/microstructures included in the collected part of the layer.